#![allow(dead_code, deprecated, unused_variables, unused_mut)]
fn main() {
    let mut slice: &mut [_] = &mut ['a', 'b', 'c'];
    let first = slice.split_off_first_mut().unwrap();
    *first = 'd';
    assert_eq!(slice, & ['b', 'c']);
    assert_eq!(first, &'d');
}